What is the difference between new/delete and malloc/free?

Question

What is the difference between new/delete and malloc/free?

Related (duplicate?): In what cases do I use malloc vs

Answer 1

The main difference between new and malloc is that new invokes the object's constructor and the corresponding call to delete invokes the object's destructor.

There are other differences:

• new is type-safe, malloc returns objects of type void*

• new throws an exception on error, malloc returns NULL and sets errno

• new is an operator and can be overloaded, malloc is a function and cannot be overloaded

• new[], which allocates arrays, is more intuitive and type-safe than malloc

• malloc-derived allocations can be resized via realloc, new-derived allocations cannot be resized

• malloc can allocate an N-byte chunk of memory, new must be asked to allocate an array of, say, char types

Looking at the differences, a summary is malloc is C-esque, new is C++-esque. Use the one that feels right for your code base.

Although it is legal for new and malloc to be implemented using different memory allocation algorithms, on most systems new is internally implemented using malloc, yielding no system-level difference.